Control device, agricultural machine, construction machine, control method, and control program

Abstract

Even if the voltage value of the output voltage of the battery that applies voltage to the holding mechanism that keeps the electric motor that drives the work equipment of the work vehicle stopped falls below a threshold value, it is possible to prevent the electric motor from suddenly stopping unintentionally. [Solution] The control device controls an electric motor that drives a work machine equipped on a work vehicle, and a holding mechanism connected to a voltage holding circuit that maintains a voltage above a predetermined voltage even when the voltage value of the voltage output from the battery falls below a threshold, the holding mechanism maintaining the electric motor in a stopped state when no voltage is applied and releasing the electric motor from the stopped state when the voltage is applied, and is equipped with an acquisition unit that acquires voltage information regarding the voltage value of the voltage output from the battery, and a control unit that controls the electric motor to stop within a predetermined period of time when the voltage value falls below the threshold.

Description

[Technical Field]

[0001] The present disclosure relates to a control device, an agricultural machine, a construction machine, a control method, and a control program. [Background technology]

[0002] Patent Document 1 discloses a portable electric agricultural machine (1) comprising a battery (2), a motor (3) driven by the battery (2), a working unit (4) operated by the rotation of the motor (3), and a control unit (5) for controlling the motor (3), wherein the control unit (5) comprises a battery voltage detection unit (5A) for detecting the voltage of the battery (2), and a motor control unit (5B) for stopping the rotation of the motor (3) when the voltage detected by the battery voltage detection unit (5A) falls below a set voltage, and wherein the control unit (5) is set so that the set voltage leaves enough battery capacity to operate the working unit (4) continuously for a predetermined period of time. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-144584 Summary of the Invention [Problem to be solved by the invention]

[0004] In work vehicles equipped with a work implement, such as agricultural machinery or construction machinery, there are cases where it is necessary to keep the work implement stopped. When the work implement is driven by a hydraulic pump, the work implement can be kept stopped simply by closing a valve that controls the hydraulic pressure. In contrast, when the work implement is driven by an electric motor, maintaining the work implement stopped requires energy to maintain the electric motor at 0 rpm, which is inefficient. For this reason, providing a holding mechanism to keep the electric motor stopped is considered. Here, if the holding mechanism is configured to keep the electric motor stopped when no voltage is applied and to release the electric motor from the stopped state when voltage is applied, if some abnormality occurs and the voltage value of the battery output voltage drops below a threshold, the holding mechanism will unintentionally hold the electric motor stopped, which could result in a malfunction such as a sudden stop of the work implement.

[0005] The present disclosure aims to provide a control device, agricultural machinery, construction machinery, control method, and control program that can prevent an electric motor from suddenly stopping unintentionally even when the voltage value of the output voltage of a battery that applies voltage to a holding mechanism that keeps the electric motor that drives the work equipment of a work vehicle stopped drops below a threshold value. [Means for solving the problem]

[0006] The control device according to the first aspect of the present disclosure is a control device (7) that controls an electric motor (54a) that drives a work machine (5) equipped on a work vehicle (100), and a holding mechanism (55) connected to a voltage holding circuit that holds a voltage equal to or higher than a predetermined voltage even when the voltage value of the voltage output from a battery (11) falls below a threshold value, the holding mechanism holding the electric motor in a stopped state when no voltage is applied and releasing the stopped state of the electric motor when the voltage is applied, and the control device includes an acquisition unit (70) that acquires voltage information related to the voltage value of the voltage output from the battery, and a control unit (72) that controls the electric motor to stop within a predetermined period of time when the voltage value falls below the threshold value.

[0007] A control method according to a second aspect is a control method in which at least one processor (21A) controls a holding mechanism connected to a voltage holding circuit that holds a voltage equal to or higher than a predetermined voltage even when the voltage value of the voltage output from a battery falls below a threshold, the holding mechanism holding the electric motor in a stopped state when no voltage is applied, and releasing the electric motor from the stopped state when the voltage is applied, wherein the at least one processor (21A) executes processing that includes acquiring voltage information regarding the voltage value of the voltage output from the battery, and when the voltage value falls below a threshold, performing control to stop the electric motor within the predetermined period.

[0008] The control program (23A) according to the third aspect is a control program (23A) for controlling an electric motor that drives a work machine equipped on a work vehicle, and a holding mechanism connected to a voltage holding circuit that holds a voltage equal to or higher than a predetermined voltage even when the voltage value of the voltage output from the battery falls below a threshold, the holding mechanism holding the electric motor in a stopped state when no voltage is applied, and releasing the electric motor from the stopped state when the voltage is applied, and causes at least one processor to execute processing including acquiring voltage information regarding the voltage value of the voltage output from the battery, and when the voltage value falls below the threshold, performing control to stop the electric motor within the predetermined period. [Effects of the Invention]

[0009] According to the present disclosure, even if the voltage value of the output voltage of the battery that applies voltage to the holding mechanism that keeps the electric motor that drives the work equipment of the work vehicle stopped falls below a threshold value, it is possible to prevent the electric motor from suddenly stopping unintentionally. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a vehicle 100 equipped with a control device 7 according to an embodiment of the present disclosure. [Figure 2]FIG. 2 is a cross-sectional view of the electric cylinder 54. [Figure 3] FIG. 3 is a diagram for explaining the holding mechanism 55. As shown in FIG. [Figure 4] FIG. 4 is a diagram illustrating a hardware configuration of the control device 7 according to the embodiment of the present disclosure. [Figure 5] FIG. 5 is a diagram showing an example of the configuration of a voltage holding circuit. [Figure 6] FIG. 6 is a diagram showing an example of the configuration of a drive unit 60 including a rotating electric machine 54a and an inverter 10. [Figure 7] FIG. 7 is a block diagram showing an example of the functional configuration of the CPU 21A of the control device 7. As shown in FIG. [Figure 8] FIG. 8 is a timing chart of the battery output voltage and the like. [Figure 9] FIG. 9 is a flowchart of the control process according to the control program 23A executed by the CPU 21A of the control device 7. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0012] FIG. 1 is a diagram showing a vehicle 100 equipped with a control device 7 according to an embodiment of the present disclosure. The vehicle 100 is a work vehicle used in agriculture or the construction industry, and may be interpreted as an agricultural construction machine (hereinafter, agricultural construction machine). The agricultural construction machine may include agricultural machinery and construction machinery. The agricultural construction machine may include an electric tractor, an electric wheel loader, an electric bulldozer, an electric excavator, an electric crane, and the like. FIG. 1 shows an electric excavator as an example of agricultural machinery. The agricultural construction machine may include a vehicle 100 that moves using crawlers as well as a vehicle 100 that moves using tires. The control device 7 according to the present disclosure may be provided in a vehicle 100 other than an agricultural construction machine. The control device 7 may be interpreted as a device that controls a rotating electric machine 54a, which is an example of an electric motor that drives a work implement 5 provided on the vehicle 100.

[0013] The vehicle 100 may include a traveling device 2 and a main body 3. The traveling device 2 may be provided below the main body 3 and may support the main body 3 so that it can rotate freely in the horizontal direction. The traveling device 2 may include a pair of left and right crawlers 2a. The main body 3 may include a cab 4 in which an operator rides, a work implement 5 provided in front of the cab 4, a battery 6, and a control device 7.

[0014] (Control device 7)

[0015] The control device 7 may be interpreted as a device that controls one or more electric cylinders 54. Specifically, the control device 7 may independently control the rotation speed, rotation direction, rotation torque (hereinafter, torque), etc. of the rotating electric machine 54a included in each of, for example, three electric cylinders 54. For example, the control device 7 may rotate the rotating electric machine 54a included in the electric cylinder 54 that drives the boom 51 in a first rotation direction, while rotating the rotating electric machine 54a included in the electric cylinder 54 that drives the arm 52 in a second rotation direction opposite to the first rotation direction. At this time, the control device 7 may stop the rotation of the rotating electric machine 54a included in the electric cylinder 54 that drives the bucket 53.

[0016] (Battery 6)

[0017] The battery 6 is a storage battery for supplying power to the rotating electrical machine 54a. The battery 6 may be, for example, a lithium ion battery or a fuel cell.

[0018] (Work machine 5)

[0019] The work implement 5 may have a multi-joint structure including a boom 51, an arm 52, and a bucket 53. The boom 51 may be supported so as to be swingable in the vertical direction relative to the cab 4. The arm 52 may be supported so as to be swingable at the tip of the boom 51. The bucket 53 may be supported so as to be swingable at the tip of the arm 52. Each of the boom 51, the arm 52, and the bucket 53 may be driven by an electric cylinder 54.

[0020] (Electric cylinder 54)

[0021] The electric cylinder 54 may be interpreted as a mechanism in which the rod 54b moves back and forth when driven by the rotating electric machine 54a. The work machine 5 of the present disclosure uses a ball screw type electric cylinder 54, but the electric cylinder 54 is not limited to the ball screw type and may be of another type, for example, a linear motor type.

[0022] As shown in FIG. 2, the electric cylinder 54 may include a rotating electric machine 54a, a speed reducing mechanism 54c, a case 54d, a nut 54e, a ball screw 54f, and a rod 54b.

[0023] The reduction mechanism 54c reduces the rotation speed of the rotating electric machine 54a and transmits the torque of the rotating electric machine 54a to the ball screw 54f in the case 54d. The reduction mechanism 54c may reduce the rotation speed by using, for example, a small-diameter first pulley 54c1 connected to the rotating shaft 54a1 of the rotating electric machine 54a, a large-diameter second pulley 54c2 connected to the ball screw 54f, and a belt 54c3 connecting the first pulley 54c1 and the second pulley 54c2. The configuration of the reduction mechanism 54c is not limited thereto, and the reduction mechanism 54c may reduce the rotation speed by using, for example, a small-diameter gear connected to the rotating shaft 54a1 of the rotating electric machine 54a and a large-diameter gear connected to the ball screw 54f.

[0024] The ball screw 54f may convert the rotational motion of the rotating electric machine 54a into the linear motion of linearly moving members such as the nut 54e and the rod 54b. The ball screw 54f may include a screw shaft 54f1 and balls 54f2. The balls 54f2 may be interpreted as rolling elements provided between the nut 54e and the screw shaft 54f1.

[0025] When the rotating electric machine 54a rotates, i.e., when the rotary shaft 54a1 rotates, the torque of the rotating electric machine 54a is transmitted to the ball screw 54f. As the ball screw 54f rotates, the rotational motion of the ball screw 54f is converted into linear motion of the nut 54e provided in the case 54d. As a result, the rod 54b connected to the nut 54e reciprocates, i.e., moves forward and backward, relative to the case 54d.

[0026] The rotating shaft 54a1, the reduction mechanism 54c, the ball screw 54f, the nut 54e, etc. may be interpreted as a mechanical element 540 that moves the rod 54b, which drives the work machine 5, back and forth. More strictly, the rotating shaft 54a1, the first pulley 54c1, the belt 54c3, the second pulley 54c2, the ball screw 54f, and the nut 54e may be interpreted as a mechanical element 540 that moves the rod 54b back and forth.

[0027] Although not shown in FIGS. 1 and 4, the pair of left and right crawlers 2a and the rotating part that rotates the cab 4 are also examples of work machines driven by the rotating electric machine 54a.

[0028] As shown in FIG. 3, the rotating electric machine 54a is provided with a holding mechanism 55. The holding mechanism 55 locks the rotating shaft 54a1 of the rotating electric machine 54a when no voltage is applied from the battery 11 (see FIG. 4), thereby maintaining the stopped state of the rotating electric machine 54a. As a result, the rotating shaft 54a1 becomes non-rotatable, and a load such as the boom 51 connected to the electric cylinder 54 is maintained stopped. Note that the battery 6 is a high-voltage battery, while the battery 11 is a low-voltage battery (e.g., 12 V or 24 V). Furthermore, when voltage is applied from the battery 11, the holding mechanism 55 unlocks the rotating shaft 54a1 of the rotating electric machine 54a, thereby releasing the stopped state of the rotating electric machine 54a. As a result, the rotating shaft 54a1 becomes rotatable, and the stopped state of the load such as the boom 51 connected to the electric cylinder 54 is released. Whether or not a voltage is applied to the holding mechanism 55 is controlled by the control device 7. In the example of FIG. 3, the holding mechanism 55 is configured to be provided inside the rotating electric machine 54a, but it may also be configured to be provided outside the rotating electric machine 54a.

[0029] In the following, locking the rotating shaft 54a1 of the rotating electric machine 54a may be simply referred to as locking the rotating electric machine 54a, and unlocking the rotating shaft 54a1 of the rotating electric machine 54a may be simply referred to as unlocking the rotating electric machine 54a.

[0030] Next, the hardware configuration of the control device 7 will be described with reference to Fig. 4. Fig. 4 is a diagram showing the hardware configuration of the control device 7 according to an embodiment of the present disclosure. The control device 7 includes a control unit 21, a communication unit 22, and a storage unit 23.

[0031] The control unit 21 is configured as a device including a general computer. The control unit 21 includes a CPU (Central Processing Unit) 21A, a ROM (Read Only Memory) 21B, a RAM (Random Access Memory) 21C, and an input / output interface (I / O) 21D. The CPU 21A, ROM 21B, RAM 21C, and I / O 21D are connected to each other via a bus 21E. The bus 21E includes a control bus, an address bus, a data bus, etc.

[0032] The I / O 21D is connected to a communication unit 22, a storage unit 23, and a sensor group 200. The communication unit 22 is an interface for communicating with external devices such as the inverter 10, the holding mechanism 55, the voltage holding circuit 80, and the vehicle controller 30. Although only one holding mechanism 55 and one voltage holding circuit 56 are shown in FIG. 4 for convenience, a holding mechanism 55 and a voltage holding circuit 80 are provided for each rotating electric machine 54a. The voltage holding circuit 80 may be provided in the control device 7 or in the holding mechanism 55.

[0033] The storage unit 23 is configured as a non-volatile external storage device such as a hard disk, etc. The storage unit 23 stores a control program 23A.

[0034] The CPU 21A is an example of a computer. The term "computer" here refers to a processor in a broad sense, and includes a general-purpose processor (e.g., the CPU 21A) or a dedicated processor (e.g., a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device, etc.).

[0035] The control program 23A may be stored in a non-volatile non-transitory recording medium or distributed via a network and appropriately installed in the control device 7, thereby being stored in the storage unit 23. The control program 23A may also be appropriately updated by so-called OTA (Over The Air).

[0036] Examples of non-volatile non-transitory recording media include CD-ROMs (Compact Disc Read Only Memory), magneto-optical disks, HDDs (Hard Disk Drives), DVD-ROMs (Digital Versatile Disc Read Only Memory), flash memory, and memory cards.

[0037] The sensor group 200 may include a wheel speed sensor, an acceleration sensor, a current sensor, an accelerator sensor, a temperature sensor, a gradient sensor, a brake sensor, a yaw rate sensor, a rotation speed sensor, and the like.

[0038] The sensor group 200 may also include a sensor that detects at least one of the speed of the vehicle 100, the speed of the work implement 5, the position of the work implement 5, the torque of the work implement 5, and the propulsive force of the work implement 5.

[0039] The rotation speed sensor may be understood as a sensor for detecting the rotation angle and rotation speed of the rotating electric machine 54a. The rotation speed sensor is, for example, a resolver or a rotary encoder, and detects the rotation angle and rotation speed of the rotor of the rotating electric machine 54a. A signal indicating the rotation speed detected by the rotation speed sensor is input to the control device 7.

[0040] The current sensor may be understood as a sensor for detecting the value of the current flowing through the rotating electric machine 54a. As an example, the current sensor detects the current flowing through any two windings (for example, the V phase and the W phase) among the windings of the U phase, V phase, and W phase. A signal indicating the value of the drive current detected by the current sensor is input to the control device 7.

[0041] The temperature sensor may be understood as a sensor for detecting the temperatures of a plurality of switch elements included in the inverter 10. A signal indicating the temperature detected by the temperature sensor is input to the control device .

[0042] The sensor group 200 also includes sensors that detect the amount of operation of an operating lever or the like that operates each work machine 5.

[0043] The inverter 10 may convert the DC power supplied from the battery 6 into AC power in accordance with instructions from the control device 7, and supply the AC power to the rotating electric motors 54a in the electric cylinders 54 provided in each of the boom 51, arm 52, and bucket 53, thereby controlling the rotation of the rotating electric motors 54a.

[0044] The boom 51, arm 52, bucket 53, etc. are connected to each of the electric cylinders 54, and these may be considered as part of the load of the electric cylinder 54 or the rotating electric machine 54a.

[0045] 5 is a diagram showing an example of the configuration of the voltage holding circuit 80. The voltage holding circuit 80 is a circuit that holds a voltage equal to or higher than a predetermined voltage even when the voltage value of the voltage output from the battery 11 falls below a threshold value.

[0046] As shown in FIG. 5, the voltage holding circuit 80 includes a holding unit 81 and a voltage monitoring unit 82.

[0047] The holding unit 81 includes a diode 83 and a capacitor 84. The anode of the diode 83 is connected to the positive side of the battery 11 and the voltage monitoring unit 82. The cathode of the diode 83 is connected to the holding mechanism 55 and one end of the capacitor 84. The other end of the capacitor 84 is connected to the negative side of the battery 11.

[0048] With this configuration, even when the voltage value output from battery 11 falls below the threshold, the voltage output from holding unit 81 does not immediately decrease but gradually decreases due to the power stored in capacitor 84. The rate at which the voltage decreases is determined by the capacitance of capacitor 84. That is, the larger the capacitance of capacitor 84, the slower the rate at which the voltage decreases, and the smaller the capacitance of capacitor 84, the faster the rate at which the voltage decreases.

[0049] The predetermined period is set to the period from when the voltage value output from battery 11 falls below the threshold value to when the voltage falls to the minimum voltage necessary to maintain the stopped state of the electric motor. A capacitor with a capacity corresponding to the predetermined period is used as capacitor 84.

[0050] The voltage monitoring unit 82 outputs the voltage value of the voltage output from the battery 11 as voltage information to the control unit 72. Note that the voltage monitoring unit 82 may notify the control device 7 when the voltage value of the voltage output from the battery 11 becomes equal to or lower than a threshold value.

[0051] 6 is a diagram showing an example of the configuration of a drive unit 60 including a rotating electric machine 54a and an inverter 10. The rotating electric machine 54a includes a stator 153, a rotor 154, a current sensor 203, and a rotation speed sensor 211. The rotating electric machine 54a is a three-phase motor generator, and the stator 153 has windings 155U, 155V, and 155W of multiple phases. The winding 155U is a U-phase winding, the winding 155V is a V-phase winding, and the winding 155W is a W-phase winding. The current sensor 203 detects, for example, the current flowing through the winding 155V and the current flowing through the winding 155W. The rotation speed sensor 211 is, for example, a resolver, and detects the rotation angle and rotation speed of the rotor 154.

[0052] The inverter 10 has six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd. Hereinafter, when there is no need to distinguish between the six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd, the six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd will be referred to as "power elements 156." These power elements 156 may be interpreted as inverter elements or switch elements. Each power element 156 is, for example, a power transistor. The power elements 156Uu and 156Ud are U-phase power elements, the power elements 156Vu and 156Vd are V-phase power elements, and the power elements 156Wu and 156Wd are W-phase power elements. Power elements 156Uu and 156Ud are bridge-connected to winding 155U, power elements 156Vu and 156Vd are bridge-connected to winding 155V, and power elements 156Wu and 156Wd are bridge-connected to winding 155W.

[0053] The inverter 10 has a plurality of temperature sensors 157. The temperature sensor 157 may be provided for each of the plurality of power elements 156.

[0054] The vehicle controller 30 transmits vehicle state information relating to the vehicle state of the vehicle 100 to the control device 7. The vehicle state information includes, for example, information on whether or not an abnormal state has occurred in which rotation of the rotating electric machine 54a should be stopped, and, if an abnormal state has occurred, information on the details of the abnormal state.

[0055] Abnormal conditions in which the rotation of the rotating electric machine 54a should be stopped include, but are not limited to, a condition in which a failure occurs in the rotating electric machine 54a, a condition in which the inverter 10 fails, a condition in which the harness system related to at least one of the rotating electric machine 54a and the inverter 10 fails, a condition in which the charge amount of the battery 6 is close to full charge and regeneration is not possible, and the like.

[0056] Based on the vehicle status information transmitted from the vehicle controller 30, if an abnormal condition has occurred that requires the rotation of the rotating electric machine 54a to be stopped, the control device 7 controls the holding mechanism 55 so that no voltage is applied to the holding mechanism 55, thereby locking the rotating electric machine 54a.

[0057] Next, an example of the functional configuration of the CPU 21A of the control device 7 will be described with reference to FIG.

[0058] Fig. 7 is a block diagram showing the functional configuration of the CPU 21A of the control device 7. As shown in Fig. 7, the CPU 21A functionally includes an acquisition unit 70 and a control unit 72. The CPU 21A functions as each functional unit by reading and executing a control program 23A stored in the storage unit 23.

[0059] The acquisition unit 70 acquires voltage information relating to the voltage value of the voltage output from the battery 11 from the voltage monitoring unit 82. The acquisition unit 70 acquires voltage information notified from the voltage holding circuit 80 or acquires voltage information by monitoring the voltage output from the battery 11. In this embodiment, the acquisition unit 70 acquires the voltage value of the voltage output from the battery 11 from the voltage monitoring unit 82 of the voltage holding circuit 80 as voltage information.

[0060] When the voltage value of the voltage output from the battery 11 becomes equal to or less than a threshold, the control unit 72 performs control to stop the rotating electric machine 54a before a predetermined period of time has elapsed. Here, the threshold is set to a voltage value at which the holding mechanism 55 is activated and the rotating electric machine 54a is locked when the voltage value of the voltage applied to the holding mechanism 55 becomes equal to or less than the threshold.

[0061] Furthermore, as mentioned above, the predetermined period is set to the period from when the voltage value of the voltage output from battery 11 falls below the threshold value to the point before the voltage drops to the minimum voltage required to maintain the electric motor in a released stopped state.

[0062] 8, for example, assume that the output voltage of the battery 11 is interrupted due to some abnormality at time t1. In this case, the output signal output from the voltage monitoring unit 82, i.e., the voltage value of the output voltage of the battery 11, becomes 0, i.e., is equal to or lower than the threshold value. Therefore, the control unit 72 performs stop control to stop the rotating electric machine 54a during the period from time t1, when the voltage value of the voltage output from the battery 11 becomes equal to or lower than the threshold value, to time t2, which is before time t3, when the voltage value of the voltage output from the battery 11 drops to the minimum voltage V1 necessary to maintain the stopped state of the rotating electric machine 54a.

[0063] That is, even if the voltage holding circuit 80 cuts off the output voltage of the battery 11, the output voltage output from the voltage holding circuit 80 gradually decreases until the predetermined period of time has elapsed, at time t2, but the output voltage is maintained at or above the minimum voltage V1, so the rotating electric machine 54a remains unlocked. Then, the control unit 72 locks the rotating electric machine 54a at time t2. This makes it possible to prevent the rotating electric machine 54a from suddenly stopping unintentionally even if some abnormality occurs and the output voltage from the battery 11 falls below the threshold.

[0064] In addition, when the voltage value of the output voltage of the battery 11 becomes equal to or lower than a threshold value while the holding mechanism 55 releases the stopped state of the rotating electric machine 54a, the control unit 72 may perform control to stop the rotating electric machine 54a until a predetermined period has elapsed, i.e., by time t2.

[0065] In addition, if the voltage value of the output voltage of the battery 11 becomes equal to or lower than a threshold value while the rotating electric machine 54a is operating, the control unit 72 may perform control to stop the rotating electric machine 54a before a predetermined period of time has elapsed.

[0066] Furthermore, when the voltage value of the output voltage of the battery 11 becomes equal to or lower than a threshold value, the control unit 72 may perform control so that the output torque of the rotating electric machine 54a becomes zero before a predetermined period of time has elapsed. By making the output torque zero, the work machine 5 or the like driven by the rotating electric machine 54a can be stopped by inertia.

[0067] Furthermore, when the voltage value of the output voltage of the battery 11 becomes equal to or lower than a threshold value, the control unit 72 may perform control so that the output torque of the rotating electric machine 54a gradually decreases until a predetermined period of time has elapsed. This allows the work machine 5 and the like to be stopped safely.

[0068] Next, a flowchart of the control process executed by the CPU 21A will be described with reference to Fig. 9. The control process of Fig. 9 is executed repeatedly. The control process of Fig. 9 is executed for each of the plurality of rotating electrical machines 54a.

[0069] In step S100, the CPU 21A determines the state of the holding mechanism 55. That is, it determines whether the holding mechanism 55 is locking or unlocking the rotating electric machine 54a.

[0070] In step S101, the CPU 21A calculates a torque corresponding to an operation amount instructed by a user for the work machine 5 driven by the rotary electric machine 54a.

[0071] In step S102, the CPU 21A determines whether the determination result in step S100 is that the rotating electric machine 54a is locked. If the rotating electric machine 54a is locked, the process proceeds to step S106, and if the rotating electric machine 54a is unlocked, the process proceeds to step S103.

[0072] In step S103, the CPU 21A determines whether the rotating electric machine 54a is operating. If the rotating electric machine 54a is operating, the process proceeds to step S106, and if the rotating electric machine 54a is not operating, the process proceeds to step S104.

[0073] In step S104, the CPU 21A determines whether the voltage value of the output voltage of the battery 11 detected by the voltage monitoring unit 82 has fallen below the threshold value. If the voltage value of the output voltage of the battery 11 has fallen below the threshold value, the process proceeds to step S105, and if the voltage value of the output voltage of the battery 11 has not fallen below the threshold value, the process proceeds to step S106.

[0074] In step S105, the CPU 21A sets the torque of the rotary electric machine 54a to zero.

[0075] In step S106, the CPU 21A sets the final torque of the rotating electric machine 54a and controls the inverter 10 so that the rotating electric machine 54a is driven at the set final torque. Specifically, if the determination in step S102 is affirmative and the process proceeds to step S106, if the determination in step S103 is affirmative and the process proceeds to step S106, or if the determination in step S104 is negative and the process proceeds to step S106, the torque calculated in step S101 is set as the final torque. In addition, if the process proceeds from step S105 to step S106, the torque set in step S105 is set as the final torque.

[0076] As described above, in this embodiment, even if the output voltage of the battery 11 is interrupted due to some abnormality, the voltage output to the holding mechanism 55 does not immediately decrease, but is gradually decreased by the voltage holding circuit 80. Therefore, even if some abnormality occurs and the output voltage from the battery 11 falls below the threshold, it is possible to prevent the rotating electric machine 54a from suddenly stopping unintentionally.

[0077] The present disclosure is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present disclosure.

[0078] Furthermore, the configuration of the control device 7 described in the above embodiment (see Figure 4) is just one example, and it goes without saying that unnecessary parts may be deleted or new parts may be added within the scope of the gist of the technology of the present disclosure.

[0079] Furthermore, the processing flow of the control program 23A described in the above embodiment (see FIG. 9) is also an example, and it goes without saying that unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged within the scope of the gist of the technology of the present disclosure.

[0080] The controller and methods described herein may be implemented by a special-purpose computer having a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by a special-purpose computer having a processor configured with dedicated hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special-purpose computers configured by a combination of a processor executing a computer program and one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0081] The following notes are provided regarding the technology of the present disclosure.

[0082] <Additional Notes> (Appendix 1) an electric motor (54a) for driving a work implement (5) provided in the work vehicle (100); a holding mechanism (55) connected to a voltage holding circuit that holds a voltage equal to or higher than a predetermined voltage even when the voltage value of the voltage output from the battery (11) falls below a threshold, the holding mechanism holding the stopped state of the electric motor when no voltage is applied and releasing the stopped state of the electric motor when the voltage is applied; A control device (7) for controlling the an acquisition unit (70) that acquires voltage information relating to a voltage value of a voltage output from the battery; a control unit (72) that performs control to stop the electric motor before a predetermined period of time has elapsed when the voltage value becomes equal to or less than a threshold value; A control device comprising: (Appendix 2) The control unit controls the electric motor to stop before the predetermined period has elapsed when the voltage value becomes equal to or less than a threshold value while the holding mechanism releases the stopped state of the electric motor. 10. The control device of claim 1. (Appendix 3) The acquisition unit acquires the voltage information notified from the voltage holding circuit or acquires the voltage information by monitoring the voltage output from the battery. 10. The control device according to claim 1 or 2. (Appendix 4) When the voltage value becomes equal to or lower than the threshold value while the electric motor is in operation, the control unit performs control to stop the electric motor before the predetermined period has elapsed. 4. The control device according to any one of appendices 1 to 3. (Appendix 5) When the voltage value becomes equal to or less than a threshold value, the control unit controls the electric motor so that the output torque of the electric motor becomes zero before the predetermined period of time elapses. 5. The control device according to any one of appendices 1 to 4. (Appendix 6) When the voltage value becomes equal to or less than the threshold value, the control unit controls the electric motor so that the output torque of the electric motor gradually decreases until the predetermined period of time has elapsed. 5. The control device according to any one of appendices 1 to 4. (Appendix 7) The voltage holding circuit is a circuit that holds a voltage equal to or higher than a minimum voltage required to maintain a state in which the stopped state of the electric motor is released until the predetermined period has elapsed after the voltage value has fallen below a threshold value. 7. The control device according to any one of appendices 1 to 6. (Appendix 8) The voltage holding circuit notifies, as the voltage information, that the voltage value of the voltage output from the battery has become equal to or lower than a threshold value. 8. The control device according to any one of appendices 1 to 7. (Appendix 9) An agricultural machine equipped with the control device according to any one of Supplementary Notes 1 to 8. (Appendix 10) A construction machine equipped with the control device according to any one of appendices 1 to 8. (Appendix 11) an electric motor that drives a work implement provided in the work vehicle; a holding mechanism connected to a voltage holding circuit that holds a voltage equal to or greater than a predetermined voltage even when the voltage value of the voltage output from the battery falls below a threshold, the holding mechanism holding the electric motor in a stopped state when no voltage is applied and releasing the electric motor from the stopped state when the voltage is applied; A control method for controlling At least one processor (21A) acquiring voltage information relating to a voltage value of a voltage output from the battery; When the voltage value becomes equal to or less than a threshold value, control is performed to stop the electric motor within the predetermined period. A control method for executing a process including: (Appendix 12) an electric motor that drives a work implement provided in the work vehicle; a holding mechanism connected to a voltage holding circuit that holds a voltage equal to or greater than a predetermined voltage even when the voltage value of the voltage output from the battery falls below a threshold, the holding mechanism holding the electric motor in a stopped state when no voltage is applied and releasing the electric motor from the stopped state when the voltage is applied; A control program (23A) for controlling At least one processor has acquiring voltage information relating to a voltage value of a voltage output from the battery; When the voltage value becomes equal to or less than a threshold value, control is performed to stop the electric motor within the predetermined period. A control program that executes processing including the above. [Explanation of symbols]

[0083] 2 Running gear 2a Crawler 3 Main unit 4 Cab 5 Work equipment 6 Battery 7 Control Device 10 Inverter 11 Battery 21 Control Unit 22 Communications Department 23 Memory section 23A Control Program 30 Vehicle Controller 54 Electric cylinder 54a Rotating Electric Machine 55 Retention mechanism 60 Drive unit 70 Acquisition Department 72 Control Unit 80 Voltage holding circuit 81 Holding part 82 Voltage monitoring unit 100 vehicles 200 sensors

Claims

1. an electric motor (54a) for driving a work implement (5) provided on the work vehicle (100); a holding mechanism (55) connected to a voltage holding circuit that holds a voltage equal to or higher than a predetermined voltage even when the voltage value of the voltage output from the battery (11) falls below a threshold, the holding mechanism holding the stopped state of the electric motor when no voltage is applied and releasing the stopped state of the electric motor when the voltage is applied; A control device (7) for controlling an acquisition unit (70) that acquires voltage information relating to a voltage value of a voltage output from the battery; a control unit (72) that performs control to stop the electric motor before a predetermined period of time has elapsed when the voltage value becomes equal to or less than a threshold value; A control device comprising:

2. The control unit controls the electric motor to stop before the predetermined period has elapsed when the voltage value becomes equal to or less than a threshold value while the holding mechanism is releasing the stopped state of the electric motor. The control device according to claim 1 .

3. The acquisition unit acquires the voltage information notified from the voltage holding circuit or acquires the voltage information by monitoring the voltage output from the battery. The control device according to claim 1 .

4. When the voltage value becomes equal to or lower than the threshold value while the electric motor is in operation, the control unit performs control to stop the electric motor before the predetermined period has elapsed. The control device according to claim 1 .

5. When the voltage value becomes equal to or less than a threshold value, the control unit controls the electric motor so that the output torque of the electric motor becomes zero before the predetermined period of time elapses. The control device according to claim 1 .

6. When the voltage value becomes equal to or less than the threshold value, the control unit controls the electric motor so that the output torque of the electric motor gradually decreases until the predetermined period has elapsed. The control device according to claim 1 .

7. The voltage holding circuit is a circuit that holds a voltage equal to or higher than a minimum voltage required to maintain a state in which the stopped state of the electric motor is released until the predetermined period has elapsed after the voltage value has fallen below a threshold value. The control device according to claim 1 .

8. The voltage holding circuit notifies, as the voltage information, that the voltage value of the voltage output from the battery has become equal to or lower than a threshold value. The control device according to claim 1 .

9. An agricultural machine equipped with the control device according to any one of claims 1 to 8.

10. A construction machine equipped with the control device according to any one of claims 1 to 8.

11. an electric motor that drives a work implement provided in the work vehicle; a holding mechanism connected to a voltage holding circuit that holds a voltage equal to or greater than a predetermined voltage even when the voltage value of the voltage output from the battery falls below a threshold, the holding mechanism holding the electric motor in a stopped state when no voltage is applied and releasing the electric motor from the stopped state when the voltage is applied; A control method for controlling At least one processor (21A) acquiring voltage information relating to a voltage value of a voltage output from the battery; When the voltage value becomes equal to or less than a threshold value, control is performed to stop the electric motor within the predetermined period. A control method for executing a process including:

12. an electric motor that drives a work implement provided in the work vehicle; a holding mechanism connected to a voltage holding circuit that holds a voltage equal to or greater than a predetermined voltage even when the voltage value of the voltage output from the battery falls below a threshold, the holding mechanism holding the electric motor in a stopped state when no voltage is applied and releasing the electric motor from the stopped state when the voltage is applied; A control program (23A) for controlling At least one processor acquiring voltage information relating to a voltage value of a voltage output from the battery; When the voltage value becomes equal to or less than a threshold value, control is performed to stop the electric motor within the predetermined period. A control program that executes processing including the above.

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